Resilience and public mental health: key mechanism identified in multi-site RCT

Abstract Increasingly populations are exposed to adversity, or stressors. Such exposure historically has been linked to worse mental. As an urgent matter for public health, people's resilience should be improved to deal with adversity and improve their ability to cope. The RESPOND project conducted 4 randomised controlled trials (RCT) of a stepped-care intervention in vulnerable populations (healthcare workers, people in unstable housing and migrants) in 4 countries (Netherlands, Italy, Spain, and France). The intervention consists of Doing What Matters (DWM) and Problem Management Plus (PM+), developed by the World Health Organisation. This intervention is effective at reducing mental health symptoms at follow-up. The present study goes beyond this primary outcome and analyses the effect of this intervention on resilience, that is, whether it improves how people cope with adversity. Additionally, we investigate a potential mechanism of action, specifically, the general style how people appraise the adversity that they face. We use an advanced statistical method to operationalise resilience outcomes, operationalised as reactivity to stressors. Stressor exposure is measured at each timepoint and then regress this stressor exposure on mental health to compute the sample's stressor reactivity. An individual's resilience is the residual to this norm at each time point. The effect of the intervention was computed in linear mixed models using resilience as an outcome. Causal mediation analyses using the counterfactual approach were conducted with positive appraisal style of stressors as a mediator. We show that DWM and PM+ can be considered resilience interventions. Our findings identify an important resilience mechanism: the way a person evaluates the adversity. Changing the way one evaluates to a more positive evaluation drives the effect of a cost-effective resilience intervention - a causal link that was confirmed in 4 RCTs. Key messages • Resilience should be a primary outcome of mental health interventions. • The appraisal of adversity is a key mechanism of resilience.